#!/bin/sh
#
# Copyright 2015-2019 Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License,
# or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Originally written by Karl Berry.
# Please send bug reports, etc. to bug-texinfo@gnu.org.
#
# Shell wrapper for the texindex.awk program.  This is the most
# convenient way to support --options; with a #! line, it is (g)awk
# itself that interprets the options.  We want texindex --version
# to report texindex's version number, not gawk's.
# 
# So our job here is to (a) find the awk interpreter,
# and (b) find the texindex.awk script file.

mydir=`cd \`dirname $0\` && pwd`

# 
# allow user override for awk program location.
awk_binary=
awk_envvar=$TEXINDEX_AWK
if test -n "$awk_envvar"; then
  if test -s "$awk_envvar"; then
    awk_binary=$awk_envvar
  else
    echo "$0: TEXINDEX_AWK environment variable set, but value" >&2
    echo "$0: is not a readable non-empty file; ignoring: $awk_envvar" >&2
  fi
fi
#
# else use configured value for awk.
if test -z "$awk_binary"; then
  awk_binary="gawk"
fi
#
# that should never be empty, but just in case, else fall back to plain
# "awk".  (Let's not go to the trouble of searching PATH unless we get
# reports of problems.)
test -z "$awk_binary" && awk_binary=awk


# 
# finding the texindex.awk script file ...
ti_script=
#
# allow user override for script location:
ti_envvar=$TEXINDEX_SCRIPT
if test -n "$ti_envvar"; then
  if test -s "$ti_envvar"; then
    ti_script=$ti_envvar
  else
    echo "$0: TEXINDEX_SCRIPT environment variable set, but value" >&2
    echo "$0: is not a readable non-empty file; ignoring: $ti_script" >&2
  fi
fi
#
# else if script is in the same directory as us (development tree), use it:
test -z "$ti_script" && test -s "$mydir/texindex.awk" \
&& ti_script=$mydir/texindex.awk
#
# else look for script in pkgdatadir.
if test -z "$ti_script"; then
  pkgdatadir_configured="/usr/local/share/texinfo"
  test -s "$pkgdatadir_configured/texindex.awk" \
  && ti_script=$pkgdatadir_configured/texindex.awk
fi
#
# look relative to $mydir, to allow the installed tree to be moved.
if test -z "$ti_script"; then
  relative_dir=$mydir/../share/texinfo
  test -d "$relative_dir" \
  && test -s "$relative_dir/texindex.awk" \
  && ti_script=$relative_dir/texindex.awk
fi
#
# didn't find it, abort.
if test -z "$ti_script"; then
  echo "$0: could not locate texindex.awk script file, quitting." >&2
  echo "$0: (checked envvar TEXINDEX_SCRIPT ($TEXINDEX_SCRIPT)," >&2
  echo "$0:  executable dir ($mydir)," >&2
  echo "$0:  share dir relative to binary ($relative_dir)," >&2
  echo "$0:  and configured pkgdatadir ($pkgdatadir_configured).)"  >&2
  exit 1
fi

# Suppose a symlink named a\tb (four chars) is made to this script, and
# "a\tb" --help
# is invoked.  We want the output to report the program name as the
# four chars a, \, t, b, not a, tab, b.
# 
# But we pass the value using (g)awk -v, and (g)awk processes arguments
# to -v for escape sequences, so that by the time the rest of the script
# sees it, it has a tab in it.
# 
# Conclusion: we must double any backslashes before invoking gawk,
# by running the command: sed 's,\\,\\\\,g'
# 
# Sadly, since we have to do this in a shell, we need twice
# as many backslash characters in the input.  Hope it's portable across
# shells and seds.
# 
escaped0=`echo "$0" | sed 's,\\\\,\\\\\\\\,g'`
exec $awk_binary -v Invocation_name="$escaped0" -f "$ti_script" -- "$@"
